1. Field of the Invention
The present invention relates to a spotting method onto and a data reading method from a biochemical analysis unit.
2. Description Related to the Prior Art
In order to make a biochemical analysis for base sequence of substances derived from living organism (for example DNA), a biochemical analysis unit is used. In order to obtain the biochemical analysis unit, minute through holes are formed in the substrate, and porous materials and the like are pressed into each through hole to form a spot area. Thus, the spot areas are arranged on the substrate, and therefore the biochemical analysis unit is called also microarray. A method of biochemical analysis, in which the biochemical analysis unit is used, includes a spotting process, a reaction process, a data reading process, and a data analysis process. In the spotting process, a specific binding substance as a reagent (hereinafter probe) is spotted and fixed in the spot areas on the biochemical analysis unit. In the reaction process, a specific binding substance as a test body (hereinafter target) is penetrated into the spot areas, and the specific binding (the biding between the probe and the target) is made. In the data reading process a biochemical analysis data is read out from the biochemical analysis unit as a result of the specific binding reaction in each spot area. In the data analysis process, the read out analysis data is analyzed in the personal computer and the like. (see, Japanese Patent Laid-Open Publication No. 2003-215125).
Since the probe is a reagent for searching the information of expression, the molecular structure (for example base sequence, composition and the like) of the used probe is already known. As the probe, there are hormones, tumor markers, enzymes, antibodies, antigens, abzymes, receptors, other proteins, ligand, nucleic acids, cDNA, DNA, RNA, and the like, and the probe can make a specific binding to the target, whose molecular structure is not known. As the target, there are substances derived from living organism (such as hormones, tumor markers, enzymes, antibodies, antigens, abzymes, receptors, other proteins, ligand, nucleic acids, cDNA, DNA, mRNA, and the like, which are extracted and isolated from the living organism), and products obtained by performing the chemical treatments or the chemical modifications of the substances derived from living organism.
When the base sequence is searched, several sorts of the probes are fixed in respective spot areas of the biochemical analysis unit. Then in the reaction process, a solution in which the target is dissolved to a solvent is penetrated in the spot areas, and the specific binding of the target and the probe having a complementary relation to the target is made.
In order to detect the specific binding, the reaction solution contains for example a labeling substances. As the labeling substances to be used, there are fluorescent substances which generate a chemical fluorescence in a chemical reaction. After the specific binding is made, the biochemical analysis unit is cleaned to remove the reaction solution on other areas than spot areas.
In the spot area in which the specific binding is made, the labeling substances remain. Accordingly, in the data reading process, a labeling signal of the optical ray, the radioactive ray or the like generated from the labeling substances is read for detecting the specific binding. As the detecting device to be used, there is an imaging device, for example, a CCD imaging sensor for reading the optical information.
In order to form the spot area of the biochemical analysis unit, the adsorptive material is pressed onto a rear face of the substrate so as to extend thereon, and the adsorptive material is supplied into the through holes. Thereby, as part of the adsorptive material remains to form a thin layer on the rear face of the substrate, and the adsorptive materials in the neighboring through holes are connected through the thin layer on the rear face. Accordingly, the labeling material remaining in the spot area sometimes penetrates through the thin layer into the neighboring spot areas. In this case, the labeling substance spotted in one spot area generates the light also in the neighboring spot areas. Thus the light seepage occurs, and is observed as a data noise which lowers the accuracy of the data. In order to obtain the data with high accuracy, it is necessary to detect the accurate light intensity of each spot, and namely to reduce the light seepage.
Accordingly, in the publication No. 2003-215125, a light absorptive material is contained in the thin layer between the spot areas, so as to reduce the light seepage.
However, in this method in which the light absorptive material is used, the effect of reducing the light seepage is not enough. Therefore, in order to obtain the analysis data of higher accuracy, the more effective method is required.
An object of the present invention is to provide a spotting method onto and a data reading method from a biochemical analysis unit, in which the noise caused by a light seepage is reduced and the data reading is possible with high accuracy.
In order to achieve the above object and other objects, in a spotting method for fixing a probe in plural spot areas formed in a biochemical analysis unit which includes a substrate and a membrane disposed on a back of the substrate, plural holes are arranged at a predetermined pitch in the substrate, and the membrane has adsorption properties. The each spot area is constructed of the through hole and a part of the membrane charged into the through hole. In the spotting method, plural pins are pressed on a back of the membrane, and the plural pins are disposed at the predetermined pitch corresponding to the plural through holes. Then a liquid of the probe is spotted into said spot areas with a spot head from an opposite side to the pin. Note that it is preferable to spot the liquid with the substrate pressed on the pin arrangement plate. In this case, the substrate is pressed on the front surface by a contact member, which is provided for the spot head to contact around the spot area.
In a data reading method for reading a reaction result in plural spot areas formed in a biochemical analysis unit which includes a substrate and a membrane disposed on a back of the substrate, plural holes are arranged at a predetermined pitch in the substrate, and the membrane has adsorption properties. The each spot area is constructed of the through holes and a part of the membrane charged into the through holes. A probe is previously fixed in the each spot area. In the data reading method, a reaction solution containing a target as a test body passes through the spot area, and the target makes a specific binding to the probe. The data reaction result in each spot area is optically read from an opposite side to the pin.
In the present invention, the biochemical analysis unit is confronted to the pin arrangement plate, and pressed to the pin arrangement plate such that the pins of the pin arrangement plate may push the thin layer of the membrane into the corresponding through holes formed in the substrate of the biochemical analysis unit. Thereby the reaction solution is spotted on the spot area formed of the membrane in each through hole, and otherwise the result of the reaction is read as the reaction data. Therefore, the probe solution does not penetrate into the neighboring spot areas and the light from the one spot area does not mixed to that from the neighboring spot areas. Accordingly, the light seepage is prevented and the data reading is made with high accuracy.
The above objects and advantages of the present invention will become easily understood by one of ordinary skill in the art when the following detailed description would be read in connection with the accompanying drawings.
As shown in
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As the plastics, there are olefins (for example, polyethylene, polypropylene, and the like), polystyrene, acryl resin (for example, polymethylmethacrylate, and the like), polymers containing chlorine (for example, polyvinyl chloride, polyvinylidene chloride and the like), polymers containing fluorine (for example, polychlorotrifluoroethylene, and the like), polycarbonates, polyesters, (for example, polyethylene naphthalate, polyethylene telephthalate and the like), polyamide (for example nylon-6, nylon-66 and the like), polyimide, polysulfonate, polyphenylen sulfide, silicon resins (for example, polydiphenyl cyclohexane and the like), phenol resins (for example, noborac and the like), epoxy resins, polyurethane, celluloses (for example, cellulose acetate, nitrocellulose and the like), and the like. Further, there are copolymers (for example butadiene-cellulose copolymer, and the like). Furthermore the above polymers may be blended. However, the sorts of the plastics are not restricted in them.
It is preferable to use the plastics as the materials of the substrate, since the through holes are easily formed. However, in this case, the light intensity is hardly decreased. In order to decrease the light intensity moreover, preferably, metal oxide particles or glass fiber particles are added to the plastics, and dispersed therein. As the metal oxide particles, there are silicon dioxide, alumina, titanium dioxide, iron oxide, cupper oxide and the like. However, the sorts of the metal oxide are not restricted in them.
A method of forming the through holes 12 may be a punching method, a pulse discharging method, an etching method, and methods in which a laser beam (exima laser and YAG laser) is applied to the substrate. However, the method of forming the through holes is not restricted in them, and selectable depending on the material of the substrate.
In order to make the density of the through holes 12 higher, the area of a opening of the each through hole is preferably less than 5 mm2, particularly less than 1 mm2, and especially less than 0.3 mm2, more especially less than 0.01 mm2, and most especially less than 0.001 mm2. Further, when the through hole has a nearly circular shape, its diameter is preferably from 200 μm to 300 μm.
A arrangement pitch P of the through holes 12 (a distance of centers between neighboring through holes 12) is preferably 50 μm to 3000 μm, and a length L of the nearest edges between the neighboring through holes is preferably 10 μm to 1500 μm. Further, the number of the through holes 12 in a unit area is preferably at least 10/cm2, particularly at least 100/cm2, especially at least 500/cm2, most especially 1000/cm2 to 10000/cm2.
After the surface treatment, an adhesive agent is applied to a surface of the substrate 11, onto which the membrane 13 is pressed for the insertion into the through holes 12. The method of applying the adhesive agent is not restricted. However, it can be a roller coating, a wire bar coating, a dip coating, a blade coating, an air knife coating or the like. As the adhesive agent, there are styrene-butadiene rubber and acrylonitril-butadiene rubber. However, it is not restricted in them. Note that the excess adhesive agent is scratched and removed by the blade, or may be removed with use of a laser beam for preventing the generation of the impurities in the following process. Note that the processes of the surface treatment of the substrate and the application of the adhesive agent can be omitted.
After the application of the adhesive agent, the membrane 13 is pressed into the through holes 12. As the membrane 13, there are porous materials and fiber materials. Note that the porous materials and the fiber materials are used simultaneously. The membrane 13 used in the present invention may be one of the porous materials (organic, inorganic porous materials or mixture thereof), the fiber materials (organic or inorganic fiber materials). Further these may be mixed. The thickness of the membrane 13 is not restricted especially. However, it may be in the range of 100 μm to 200 μm (0.10 mm to 0.20 mm). Further, a void ratio C in volume is preferably within 10% to 90% and pores forming the void would average 0.1 μm to 50 μm in diameter, and a void ratio C in volume is a percentage of a total volume of the void to the appearance volume of the adsorptive materials.
The sorts of the organic porous materials are not restricted especially. However, they are preferably polymers, for example, cellulose derivatives (for example, nitro cellulose, regenerated cellulose, cellulose acetate, cellulose acetate butyrate, and the like), aliphatic polyamides (for example, nylon-6, nylon-6,6, nylon 4,10, and the like), polyolefines (for example, polyethylene, polypropyrene), polymers containing chlorinate (for example, polyvinyl chloride, polyvinylidene chloride and the like), fluorine resins (for example, polyvinylidene floride, polytetrafluoride and the like), polycarbonate, polysulfone, alginic acid, and derivatives thereof (for example, calcium alginate, ion complex of alginic acid/polylysine, and the like) collagen, and the like. Further, the copolymer or the complexes (or mixture) of these polymers may be used. Note that porous nylon is preferably used in view of the water absorbing properties in the present invention.
The sorts of the inorganic porous materials are not restricted. However, they are preferably metal (for example, platinum, gold, iron, silver, nickel, aluminum, and the like), metal oxide (for example, alumina, silica, titania, zeolite, and the like), salts of metals (hydroxyapatite, calcium sulfate and the like) complexes of them, and the like. Further, porous carbon materials (activated carbon and the like) may be used.
Further, organic fiber materials and the inorganic fiber materials are not restricted especially. However, as the organic fiber materials, the cellulose derivatives, aliphatic polyamides and the like can be used, and as the inorganic fiber materials, glass fiber and metal fiber can be used. Note that in order to increase the strength of the membrane 13, insoluble fiber materials can be mixed with the solvent for the porous materials.
As shown in
As shown in
The pin arrangement plate 21 is disposed at such a position on a table of a spotter that each pin 22 may contact to a center of the corresponding spot area 14 (or the corresponding through hole 12). The biochemical analysis unit 10 is shifted downwards to the pin arrangement plate 21, and pressed onto the arrangement surface of the pins 22. Each pin 22, after contacting to the thin layer 15, enters the corresponding through hole 12 while the top of each pin 22 pushes part of the thin layer 15 into the through hole 12. Besides, since the thin layer 15 is pressed, pores 23 in the thin layer 15 are squashed. In this situation is spotted the probe solution onto the spot areas 14 from a front side of the substrate 11. In the lower side of the spot areas 14, since the pores 23 are squashed, the spotted probe solution does not interpenetrate through the thin layer 15 into the neighboring spot areas 14.
Concretely, the diameter d of the top of the pin 22 is determined in the range of a formula: D-2Ts≧d≧D/2. As described above, the diameter d of the top of the pin 22 is smaller than the diameter D of the through hole 12. However, if the diameter d is too small, a contact area of the top to the thin layer 15 becomes smaller, and the pore 23 cannot be squashed in a wide area. Thus the prevention effect to the interpenetration of the probe solution into the neighboring spot areas 14 is lost. The minimal value of the diameter d of the top is about ½ of the diameter D of the through hole 12. Further, since the pin 22 enters the through hole 12 with pressing the thin layer 15, it is necessary to keep at least a margin for the thickness Ts of the thin layer 15 between the pin 22 and an inner wall of the through hole 12. Viewing it in section, since the margin is needed for the thin layer 15 to enter both sides of the pin 22, the twice of the thickness Ts is necessary as the total margin in one radial direction. Accordingly, the maximal value of the diameter d is about D-2Ts. For example, if the diameter D of the through hole 12 is 300 μm and the thickness Ts of the thin layer 15 is 30 μm, the diameter d of the top of the pin 22 is determined in the range of 150 μm to 240 μn. Otherwise, if the diameter D of the through hole 12 is the same value of 300 μn and the thickness Ts of the thin layer 15 is 50 μm, the diameter d is determined in the range of 150 μm to 200 μm.
As shown in
After spotting the probe solution, an UV-ray is irradiated on the spot areas 14 to fix the probe thereto.
In the reaction process, the specific binding reaction of the probes and a target as the test substance is made with use of a reactor 31. The reactor 31 is constructed of a reaction vessel 32, a circulating pipe 33 and a pump 34. In the reaction vessel 32, the biochemical analysis unit 10 is contained and a reaction solution 35 for performing the specific binding reaction is supplied.
The reaction solution is prepared by a preparing device for the reaction solution. In the preparing device, a target is dissolved in a solvent to prepare the reaction solution. The prepared reaction solution is contained in a tank (not shown) provided for the reactor 31. As the labeling materials, there are phosphor materials, radioactive materials, chemiluminescent materials which generate a chemiluminescence in the chemical reaction thereof, and the like. In this embodiment, the chemiluminescent materials are used. Further, introduced to perform the labeling is an indirect-labeling method, in which no labeling materials but antigens are contained in the reaction solution.
The reaction vessel 32 is provided with an inlet 36 for supplying the reaction solution and an outlet 37 for discharging the reaction solution. The biochemical analysis unit 10 is set in the reaction vessel 32 such that one surface (the lower surface in this figure) may confront the inlet 36 and another surface (the upper surface in this figure) may confront the outlet 37. The reaction solution supplied into the reaction vessel 32 penetrates into each spot area 14 from the lower side in this figure. Then, the reaction solution passes through each spot area 14 and flows to the upper side in this figure. In some of the spot areas 14, in which the probes being complementary to the target are contained, the specific binding of the probes and the targets is made. Then the reaction solution flows through the spot areas 14 and is discharged through the outlet 37 from the reaction vessel 32.
The inlet 36 and the outlet 37 are connected to the circulating pipe 33, and the reaction solution discharged from the reaction vessel 32 is fed through the pump 34 and the circulating pipe 33 to the reaction vessel 32 again. Further, when the reaction solution or the cleaning solution is supplied into or discharged from the reaction vessel 32, a supply pipe (not shown) and a discharge pipe (not shown) are respectively connected to the inlet 36 and the outlet 37. The inlet 36 and the outlet 37 are exchangeably connected to the supply pipe, the discharge pipe and the circulating pipe 33.
The procedure described above for supplying into, discharging from a chamber 32a, and circulately feeding by a pump 34 is applied in the same manner to an antigen cleaning solution, an antigen-antibody reaction solution containing an enzyme labeling antigen, an antibody cleaning solution, and a solution containing chemiluminescent substrates.
After the reaction process, the biochemical analysis unit 10 is removed from the reactor 31 and sent to the data reading process. In the data reading process, the biochemical analysis data is photoelectrically read by a detecting device 41. Since the labeling substances remain in the some spot areas in which the specific binding reaction is made, the light is generated. Otherwise, the light is not generated in the other spot areas in which the specific binding is not made. Receiving the light as the result of the specific binding reaction in the spot areas 14, the detecting device 41 generates an image data. In the data analyzing process, the image data is analyzed as the biochemical analysis data.
The detecting device 41 includes a CCD image sensor 42 which receives a light generated from the labeling substances and photoelectrically converts the light. In front of a receiving surface of the CCD image sensor 42, there is a light guide for guiding the light to photosensitive elements of the CCD image sensor 42. A light guide 43 is constructed of optical fibers whose number is corresponding to that of the spot areas 14. One end of each optical fiber confronts the receiving surface and another end confronts the corresponding spot area 14.
As shown in
Operations of the above structure will be described in the followings. In the spotting process, the pin arrangement plate 21 presses the biochemical analysis unit 10 from the rear face. The pins 22 enter the corresponding through holes 12, and push the corresponding spot areas 14 through the thin layer 15. In this situation, the spotting is made. Since the pores 23 are squashed in the pressing, the spotted probe solution does not penetrate into the neighboring spot areas 14. Thus the labeling materials don't remain in the thin layer 15 between the neighboring spot areas. Therefore the light seepage is prevented.
In the reaction process, the biochemical analysis unit 10 is set to the reaction vessel 32, and the reaction process is performed in the procedure shown in
In the data reading process, as shown in
In the above embodiment, the pins press the corresponding spot areas. However, as shown in
In the above embodiment, the indirect labeling method in which the reaction solution with target contains no labeling materials. However the direct labeling method may be applied, in which the reaction solution contains both of the target and the labeling materials.
Various changes and modifications are possible in the present invention and may be understood to be within the present invention.
Number | Date | Country | Kind |
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2003-342626 | Sep 2003 | JP | national |